Ortho-oxyazo dye.



UNITED STATES PATENT OFFICE.

FRIEDRICH SCHMIDT AND KARL SCHIRMACHER, OF HCCHST-ON-THE- MAIN, GERMANY, ASSIGNORS TO FARBWERKE, VORM. MEISTER, LUCIUS & BRIINING, OF HCCHST-ON-THE-MAIN, GERMANY, A COR- PORATION OF GERMANY.

- ORTHO-OXYAZO DYE.

Specification of Letters Patent.

Patented July 1'7, 1906.

To all whom it may concern.-

Be it known that we, FRIEDRICH SCHMIDT, Ph. D, and KARL SCHIRMACHER, Ph. D., chemists, citizen's ofthe Empire of Germany, residing at I-Itichst-on-the-Main, Germany, have invented certain new and useful Improvements in the Manufacture of Ortho- Oxymonoazo Dyestuffs, of which the following is a specification.

We have found that by combining the diazo compound of 3-amido-4-oXy-1-toluene with 1.8.3.6. dioxynaphthalene disulfonic acid (C,,,H (OH) (SO H) being the so called chromotropic acid, a valuable monoazo dyestuff may be obtained which yields beautiful blue shades of great fastness when fixed as chrome-lake on chrome-mordanted wool or dyed on unmordanted wool and subsequently developed with chromates.

The manufacture of this dyestuff is as follows: Diazotised 3.4.1-ortho-amido-paracresol is combined with chromotropic acid in a strong caustic alkalin solution or in presence of hydrate of lime.

The composition of the dyestuff in the form of the sodium salt is characterized by the following formula:

3 N N (2) on. (t) 0 \CIOHS 85in (1) (6) son Example: 12.3 kilograms of ortho-amidopara-cresol (NH .OH.CH =3:4:1) are dissolved with thirty kilograms of hydrochloric acid of about 20 Baum, a solution of 6.9 kilograms of nitrite being gradually added at 0 centigrade. This diazo solution is slowly run into a solution of thirty-eight kilograms of the disodium salt of chromotropic acid, thirty kilograms of finely-divided hydrate of lime having been stirred in. After about twelve hoursthe formation of the dyestufi is complete. It may then be acidified with hydrochloric acid and the dyestuff precipitated with common salt.

When dry, the dyestuff is a reddish-violet powder, soluble in water with a red color. The aqueous solution becomes blue-violet on addition of a solution of sodium carbonate. On addition of dilute hydrochloric acid hardly any change is produced in the color. In concentrated sulfuric acid the dyestuif dissolves with a blue-violet color. It dyes wool blue-red in an acid-bath. The dyeing of the chrome-lake is blue. On treatment with tin and hydrochloric acid the dyestuff is reduced to ortho-amido-para-cresol and amido-chromotropic acid.

Having now described our invention, what we claim is.

As a new product, the ortho-oxymonoazo dyestuff having as a sodium salt the formula:

(3) N N- 2 (1) OH 0.113(4 on gg being a reddish-violet powder, soluble in water with a red color, the aqueous solution of which becomes blue-violet on addition of a solution of sodium carbonate, while on addition of dilute hydrochloric acid hardly any change is produced in the color; in concentrated sulfuric acid the dyestuff dissolves with a blue-violet color; on reducing with tin and hydrochloric acid the dyestuff is split into ortho-amido-para-cresol and amido-chromotropic acid; it dyes wool blue-redin an acidgath, the dyeing of the chrome-lake being lue.

. In testimony that we claim the foregoing as our invention We have signed our names in presence of two subscribing witnesses.

FRIEDRICH SCHMIDT. KARL SCI-IIRMACHER. Witnesses:

ALFRED BRISBOIS, BERNHARD LEYDEGKER. 

